Device, method, and medium for recording still picture and animation

ABSTRACT

Picture signals entering a picture input device  4  are compressed by a picture compression device  5  for storing the resulting compressed picture data in a secondary storage device  7  via a primary storage device  6 . The picture compression system is switched for recording a moving picture and for recording a still picture by switching picture compression parameters of the picture compression device  5  by a picture compression system switching device  10  between those for moving picture recording and those for still picture recording.

TECHNICAL FIELD

This invention relates to an apparatus and a method for recording movingpictures and still pictures using a general-purpose standard forencoding moving pictures, such as MPEG2, and a recording medium havingmoving and still pictures recorded thereon.

BACKGROUND ART

In Japanese Laying-Open patent Publication 3-34686, there is disclosed adigital still picture signal recording/reproducing device in which, asmoving picture signals are recorded, desired still picture signals areselected from video camera output signals and recorded in a digitalmemory, such as RAM, and in which signals sequentially read out from thedigital memory are divided into plural tracks for recording on a digitalspeech recording/reproducing device.

In the digital still picture signal recording/reproducing device, thedigitally-recorded still picture signals are recorded along withidentification signals specifying that the digitized still picturesignals are signals other than speech signals, for demarcating thedigitally-recorded still picture signals from the digital speechsignals.

In the Japanese Laying-Open Patent publication 5-36205, there isdisclosed a magnetic recording device in which moving pictures can beimaged even during timer operation on the occasion of imaging a stillpicture using a timer.

In the Japanese Laying-Open Patent publication 5-115053, there isdisclosed a magnetic recording device in which a specified one ofcontiguous analog moving pictures is recorded as still picture signalsin a still picture recording area and the still picture is alsocontinuously recorded in the moving picture recording area for enablingcomprehension of the contents of the recorded still picture at the timeof reproduction of the moving picture.

In the Japanese Laying-Open Patent publication 7-193777, there isdisclosed a video camera capable of simultaneously recording the movingpicture and the still picture in which, if recording release mode isselected during recording of the still picture signals, the recordingpicture release mode is executed after completely recording the stillpicture signals for not allowing incomplete still picture to be left.

Meanwhile, in a conventional device for recording both the moving andthe still picture, the moving picturers are recorded as analog signalson a magnetic tape, whilst the still picture is recorded as PCMeddigital signals in a digital signal recording area. Thus, two channelsof the signal processing circuits, namely an analog signal processingcircuit for recording moving pictures and a digital signal processingcircuit for recording still pictures, are required, thus complicatingthe device structure. For reproducing the recorded moving and stillpictures, two reproducing circuits for coping with the two recordingsystems are required.

If a still picture is imaged during recording the moving pictures, thesame scene is recorded in duplicates by analog and digital signals. Ifonly a still picture is recorded, an analog signal recording area for amoving picture is not used. In such case, the recording capacity of therecording medium, such as a magnetic tape, is not utilized effectively.

Moreover, if a still picture is imaged during recording of movingpictures, the digital signals of the imaged still picture are recordedin the speech signal recording area, so that, during recording ofdigital signals of the still picture, speech recording is interrupted.

Thus it may be contemplated to record on the recording medium the movingpicture and the still picture by the compression system for movingpictures and by the compression system for still pictures, respectivelyusing such as MPEG standard, in order to make common use of therecording device for recording the moving picture and for recording themoving picture for enabling effective utilization of the recordingcapacity of the recording medium as well as preventing interruption ofspeech recording.

However, with the structure of simply recording compressed data formoving pictures and that for still pictures, it becomes difficult toselectively record only still pictures.

For overcoming the above drawback, it is an object of the presentinvention to provide a still/moving picture recording apparatus and astill/moving picture recording method in which a common hardwarestructure is used for recording moving pictures and still pictures andin which effective utilization can be made of the recording capacity ofthe recording medium even in case moving pictures are recorded togetherwith a still picture, and a recording medium for still and movingpictures having recorded thereon the moving pictures together with stillpictures.

It is another object of the present invention to provide an apparatusand a method and a recording medium for moving/still pictures forenabling only the still picture data to be selected and reproduced.

DISCLOSURE OF THE INVENTION

The still/moving picture recording apparatus according to the presentinvention includes picture compressing means for compressing inputpicture signals for conversion to picture data, recording means forrecording the picture data outputted by the picture compressing means ona recording medium and picture compression system switching means forswitching the picture compression parameters of the picture compressionmeans between those for moving picture recording and those for stillpicture recording for switching the picture compression system. With theabove picture compression system switching means, the compression systemis preferably switched for still picture recording to an intra-frameencoding (I-picture) or to forward predictive encoding (P-picture).Also, with the still/moving picture recording apparatus according to thepresent invention, the picture compression system is automaticallyswitched between that for moving picture recording and that for stillpicture recording for recording compressed picture data on the recordingmedium.

The still/moving picture recording apparatus according to the presentinvention includes picture compression means for generating, for themoving picture recording mode, picture data compressed based on thecompression parameters for moving picture recording, and for generating,for the still picture recording mode, compressed picture data compressedbased on compression parameters for still picture recording, andrecording means for recording picture data generated by the picturecompression means on an exchangeable recording medium. Picture datainclusive of the still picture recording mode information specifyingthat the picture is a still picture is recorded on the recording mediumfor the still picture recording mode. The still picture recording modeinformation specifying that the picture recorded is the still picturemay be such information in which the quantization coefficient of thefirst macro-block of picture data compression-encoded in accordance withthe MPEG standard is fixed at a specified value. The compressionparameters for still picture are set in meeting with for example themagnitude of the motion vector or the input picture position.

In the still/moving picture recording method wherein picture compressionparameters are switched between those for moving picture recording andthose for still picture recording, input picture signals are convertedinto compressed picture data by a picture compression system differentbetween one for moving picture recording and one for still picturerecording, and the compressed picture data is recorded on a recordingmedium. With the still/moving recording method, the picture compressionsystem is switched during still picture recording to intra-pictureencoding or to forward predictive encoding for converting the inputpicture signals to compressed picture data which is recorded on therecording medium.

In the still picture recording method according to the presentinvention, picture data compressed based on compression parameters formoving picture recording is generated for a moving picture recordingmode for recording on a recording medium and picture data compressedbased on compression parameters for still picture recording is generatedfor a still picture recording mode for recording on the recording mediumalong with the still picture recording mode information specifying thatthe picture recorded in a still picture. With the present still/movingpicture recording method, the compression parameters for still pictureprovide that, in compression encoding by MPEG as a standard forencoding, the quantization coefficient of the initial macro-block ofpicture data be fixed at a pre-set specified value, and the informationin which the quantization coefficient of the initial macro-block ofpicture data is fixed at a pre-set specified value is used as the stillpicture recording mode information. The compression parameters for stillpicture are set in meeting with for example the magnitude of the motionvector or the input picture position.

The still/moving picture recording medium according to the presentinvention has a moving picture recording area and a still picturerecording area having recorded therein compressed picture data obtainedby switching the picture compression parameters for converting inputpicture signals by picture compression systems different for movingpicture recording and for still picture recording.

The still/moving picture recording medium according to the presentinvention has a moving picture recording area and a still picturerecording area. The moving picture recording area has recorded thereinpicture data compressed based on compression parameters for movingpicture recording while the still picture recording area has recordedtherein picture data compressed based on compression parameters forstill picture recording as well as the still picture recording modeinformation specifying that the picture data recorded is a stillpicture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an illustrative structure of astill/moving picture recording device according to the presentinvention.

FIG. 2 is a block diagram showing another illustrative structure of astill/moving picture recording device according to the presentinvention.

FIG. 3 is a block diagram showing a specified illustrative structure ofa still/moving picture recording/reproducing device according to thepresent invention.

FIG. 4 is a flowchart for illustrating a sequence of operations fordetermining quantization parameters supplied to a picturecompression/expansion processor by a controller of the still/movingpicture recording/reproducing device shown in FIG. 3.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to the drawings, preferred embodiments of the presentinvention will be explained in detail.

The still/moving picture recording device according to the presentinvention is configured as shown for example in the block diagram ofFIG. 1.

A still/moving picture recording device shown in FIG. 1 includes aspeech input device 2, a speech compression device 3, as a speechprocessing device, for converting an input speech signal outputted bythe speech input device 2 into speech data, a speech input device 4, apicture compression device 5 for compressing picture data outputted bythe speech input device 4 for conversion to picture data, a recordingdata generating device 6 for transiently storing picture data outputtedby the speech compression device 3 and picture data outputted by thepicture compression device 5, packeting the transiently stored speechdata and picture data for generating packet data and for outputting thepacket data, a recording device 7 for recording the packet dataoutputted by the recording data generating device 6 on an exchangeablerecording medium 8, and a picture compression system switching device 10for switching picture compression parameters prescribing the picturecompression operating conditions for the picture compression device 5for recording moving pictures to those for still pictures and vice versafor switching the picture compression systems.

The speech input device 2 includes a microphone and speech signalprocessing circuit for amplifying speech signals collected by themicrophone. The speech compression device 3 includes an encoding circuitfor speech for converting the input speech signal into digital signalsand subsequently compressing the converted digital signals foroutputting speech data. The picture input device 4 includes an imagingoptical system, an imaging system, such as CCD, and a picture signalprocessing circuit for performing various analog signal processingoperations on the imaged picture signals.

The picture compression device 5 includes an encoding circuit for MPEG2,as an example. The picture compression device 5 is designed forcompressing a picture under picture compressing conditions designated bythe compression parameters supplied from the picture compression systemswitching device 10.

The recording data generating device 6 includes a memory for transientstorage of speech data and picture data and a data processing circuitfor packeting the transiently stored data.

The recording device 7 has a recording medium loading unit for loadingexchangeable recording mediums, such as tapes, discs or memory cards,and a recording circuit for recording packet data on the loadedrecording medium. The recording device 7 records packet data furnishedby the recording data generating unit 6 on the exchangeable recordingmediums 8.

The picture compression system changeover device 10 includes acompression parameter storage unit 11 for moving pictures, having storedtherein compression parameters for recording moving pictures, acompression parameter storage unit 12 for still pictures, having storedtherein compression parameters for recording still pictures, a parameterselection circuit 13 for selecting parameters supplied to the picturecompression device 5, and a CPU 16 for monitoring the operating statesof a moving picture recording button 14 and a still picture recordingbutton 15 for determining the recording mode and for controlling theselective switching operation of the parameter selecting circuit 13based on the selected recording mode so that the compression parametersfor recording moving pictures and those for recording still pictureswill be supplied to the picture compression device 5 during recording ofthe moving pictures and during recording of the still pictures,respectively.

The compression parameters for moving pictures prescribe the compressionratio larger than those for still pictures. The compression parametersfor moving pictures permit all of the three sorts of encoding ofintra-coded frames (I-pictures), forward predictive encoding(P-pictures) and bidirectional predictive coding (B-frames). Thecompression parameters for moving pictures are set at the time ofgenerating the picture compression data for moving pictures so that thequantization coefficients of the initial macro-block will be other than1.

The compression parameters for still pictures prescribe the compressionratio smaller than those for moving pictures. The compression parametersfor moving pictures are basically intended for intra-coded frames(I-pictures) on the condition that, if still picture recording isrequested consecutively within a pre-set time, picture encoding may becarried out by forward predictive encoding (P-pictures). When compressedpicture data for still pictures is generated, the quantizationcoefficient of the first macro-block of the compressed parameters forstill pictures is set to unity (1).

If the recording button for recording 14 is pressed down, the CPU 16judges the mode to be that for recording moving pictures and controlsthe parameter selecting button 13 to supply the compressed parametersfor recording moving pictures to the picture compression device 5. Ifthe moving picture recording button 14 continues to be pressed down, theCPU 16 continues the recording of moving pictures.

If the still picture recording button 15 is pressed down, the CPU 16judges the mode to be that for recording still pictures and controls theparameter selecting button 13 to supply the compressed parameters forrecording still pictures to the picture compression device 5. At a timepoint a one-frame still picture has been recorded as from a time pointof detecting the pressing of the still picture recording button 15, theCPU 16 causes the still picture recording mode to be terminated. Thearrangement may be so made that, during the time the still picturerecording button 15 is pressed down, the still picture recording will becontinued for the number of frames per unit time which is the same as orlesser than the moving picture recording time. That is, during the timethe still picture recording button 15 is pressed down, still picturescontinue to be recorded at a rate of 1 to 30 frames per second.

If, during the time the moving picture recording button 14 is presseddown such that the recording is going on under the moving picturerecording mode, the still picture recording button 15 is pressed down,the CPU 16 switches the picture compression parameters from those forthe moving picture to those for the still picture for one frame period.The CPU 16 may be configured so that the still picture recording modewill be continued during the time of pressing of the still picturerecording button 15.

The picture compression device 5 compresses the input picture signals,based on the picture compression parameters supplied from the picturecompression system switching device 10, for converting the input picturesignals into picture data. When generating picture compression data forstill pictures based in the compression parameters for recording stillpictures, the picture compression device 5 sets the quantizationcoefficient of the first macro-block to unity (1). When generatingpicture compression data for still pictures based on the compressionparameters for recording still pictures, the picture compression device5 sets the quantization coefficient of the first macro-block to otherthan unity (1).

By recording on the recording medium whether or not recording has beendone in the still picture recording mode or in the moving picturerecording mode, depending on whether or not the quantization coefficientof the initial macro-block is set to 1, it becomes possible toautomatically select and reproduce only the still picture data duringreproduction.

The operation of the still/moving picture recording device 1 accordingto the present invention will hereinafter be explained. On pressing themoving picture recording button 14, the CPU 16 in the picturecompression system switching device 10 judges the mode to be the movingpicture recording mode and furnishes the compression parameters forrecording moving pictures to the picture compression device 5. Based onthe compression parameters for recording moving pictures, the picturecompression device 5 compresses the input picture for outputting thecompressed picture data. The recording data generating device 6 packetsspeech data outputted by the speech compression device 3 and picturedata outputted by the picture compression device 5 to supply thepacketed data to the recording device 7. The recording device 7 recordsthe packet data on an exchangeable recording medium 8, such as a tape,disc or a memory card. This effects recording of moving pictures.

If the still picture recording button 15 is pressed, the CPU 16 in thepicture compression system switching device 10 judges the mode to be astill picture recording mode, and furnishes the compression parametersfor recording still pictures to the picture compression device 5. Basedon the compression parameters for recording still pictures, the picturecompression device 5 compresses the input picture for one frame tooutput the compressed picture data. The compressed one-frame picturedata is packeted by the recording data generating device 6 and furnishedto the recording device 7 for recording on the exchangeable recordingmedium 8.

If the still picture recording button 15 is pressed down during therecording of moving pictures, the CPU 16 in the picture compressionsystem device 10 switches the picture compression parameters supplied tothe picture compression device 5 from those for moving picture to thosefor still pictures only during one-frame period. Thus, the picturecompression device 5 reverts to the state of compressing the movingpictures after compressing the input picture based on the still picturerecording compression parameters for one frame period as from thecompressed state for moving pictures. The picture data, sequentiallyoutputted by the picture compression device 5, is packeted by therecording data generating device 6 and thence supplied to the recordingdevice 7 for recording on the exchangeable recording medium 8.

Since only the compression parameters are modified for one frame periodof recording still picture, even if the still picture is recorded duringrecording the moving pictures, but the series of moving picturerecording operations are not discontinued so that still picture can berecorded without interrupting the recording of moving pictures.Consequently, the speech recording is not interrupted during recordingof the moving pictures. Moreover, if the moving and still pictures arerecorded simultaneously, the moving and still pictures are not recordedin separate areas, but simply the compression system for one-framepicture is modified for recording the one-frame still picture, so thatthe recording capacity of the recording medium can be exploitedeffectively without wastage. Also, since the one-frame input picture isrecorded in the still picture recording mode with a low picturecompression ratio as an encoded frame reproducible within the frameitself, such as the intra-frame coded frame (I-picture), a still picturecan be recorded to a high picture quality.

In addition, since the present still picture recording device 1 recordson the recording medium data indicating whether the recording is by thestill picture recording mode or by the moving picture recording modedepending on whether or not the quantization coefficient of the initialmacro-block of picture data is fixed at 1, it becomes possible to selectand reproduce only the still picture data automatically. That is, therecording medium 8 having recorded thereon still and moving pictures ina commingled state by the above-described still/moving picture recordingdevice 1, is a still/moving picture recording medium having a movingpicture recording area having recorded therein compressed picture datacompressed based on the compression parameters for recording movingpictures and a still/moving picture recording area having recordedtherein compressed picture data compressed based on the compressionparameters for recording still pictures along with the still picturerecording mode information specifying that the compressed picture dataare those for a still picture.

In the configuration of FIG. 1, the picture compression system switchingdevice 10 has the compression parameters for recording moving picturesand those for recording a still picture and the compression parametersconforming to the recording mode are supplied from the picturecompression system switching device 10 to the picture compression device5. However, an arrangement may also be made so that compressionparameters for recording moving pictures and those for recording stillpictures are provided on the side of the picture compression device 5and so that a recording mode command indicating whether the recordingmode is that for the moving pictures or that for the still picture issupplied from the picture compression system switching device 10 to thepicture compression device 5 which then switches the picture compressionsystem depending on the supplied recording mode command.

A still/moving picture recording device 21, according to the presentinvention, may be configured as shown for example in FIG. 2.

The still/moving picture recording device 2, shown in FIG. 2, includes aspeech input device 22, a speech compression device 23 for convertingthe input speech signal outputted by the speech input device 22 intospeech data, a speech input device 24, a picture compression device 25for compressing the input picture signals outputted by the picture inputdevice 24 for conversion to picture data, a recording data generatingunit 26 for transiently storing speech data outputted by the speechcompression device 23 and the picture data outputted by the picturecompression device 25 and for packeting the transiently stored speechand picture data to form packeted output data, a recording device 27 forrecording packet data supplied by the recording data generating device26 on the exchangeable recording medium, and a picture compressionsystem switching device 30 for switching the picture compressionparameters prescribing the conditions for picture compression operationof the picture compression device 25 between those for the recording ofmoving pictures and those for recording a still picture for switchingthe picture compression system.

The speech input device 22 includes a microphone and a speech signalprocessing circuit for amplifying the speech signals collected by themicrophone. The speech compression device 23 includes an encodingcircuit for speech adapted for converting the input speech signal into adigital signal and subsequently compressing the digital signal foroutputting speech data. The picture input device 24 includes an imagingoptical system, an imaging element, such as CCD and a picture signalprocessing circuit for performing a variety of analog signal processingoperations on the imaged picture signals.

The picture compression device 25 includes, for example, an encodingcircuit for MPEG2. This picture compression device 25 is configured forcompressing a picture under picture compressing conditions specified bythe compression parameters suppled from the picture compression systemswitching device 30.

The recording data generating device 26 includes a memory fortransiently storing speech data and picture data and a data processingcircuit for packeting the transiently stored speech and picture data.

The storage device 27 includes a recording medium mounting unit forloading the exchangeable recording mediums, such as a tape, disc or amemory card, and a recording circuit for recording packet data in theloaded recording medium. The recording device records packet datasupplied from the recording data generating unit 26 on the exchangeablerecording medium.

The picture compression system switching device 30 includes acompression parameter decision unit for a moving picture 31 fordetermining the compression parameter for the moving picture, acompression parameter decision unit for still picture 32 for determiningcompression parameters for still pictures, a moving picture flag writingunit 33 fed with an output of the compression parameter decision unitfor a moving picture 31, a still picture flag writing unit 34 suppliedwith an output of the compression parameter decision unit for stillpicture 32, a parameter selection circuit 35 for selecting parameterssupplied to the picture compression device 25, and a CPU 38 formonitoring the operating state of the moving picture recording button 36and the still picture recording button 37 for determining the recordingmode and for controlling the selective switching of the parameterselection circuit 35, so that, based on the determined recording mode,the compression parameters for moving picture recording and those forstill picture recording will be supplied to the picture compressiondevice 25 during recording the moving and still pictures, respectively.

Based on the generated encoded data volume sent from the picturecompression device 25 and on the picture activity, the compressionparameter decision unit for a moving picture 31 determines thecompression parameters for recording the moving picture. The compressionparameters for moving pictures prescribe a compression rate larger thanthose for still picture. The compression parameters for moving picturespermit encoding of all three types of encoding, that is intra-codedframe (I-picture), forward prediction encoded frame (P-picture) andbackward predictive encoded frame (B-picture). The moving picture flagwriting unit 11, supplied with the output of the compression parameterdecision unit for moving picture 31 compulsorily change the compressionparameters for the moving picture to ‘2’ so that the quantizationcoefficient of the leading macro-block of the picture will be other than‘1’ for enabling the picture to be identified as the moving pictureduring reproduction.

The compression parameter decision unit for still picture 32 determinesthe compression parameters for recording the moving picture based on thedata volume from the picture compression device 25 and on pictureactivity. The compression parameters for still picture prescribe acompression rate smaller than those for still picture. The compressionparameters for still picture are basically designed for intra-framecoded frame (I-frame) and allow for picture encoding by the forwardpredictive-coded frame (P-picture) if recording of still pictures isrequested on end in a pre-set time duration. The still picture flagwriting unit 34, supplied with the output of the compression parameterdecision unit for still picture 34, compulsorily changes the compressionparameters for the moving picture to ‘1’ so that the quantizationcoefficient of the leading macro-block of the picture will be ‘1’ forenabling the picture to be identified as the still picture duringreproduction.

If the moving picture recording button 36 is pressed down, the CPU 38judges the recording mode to be the moving picture recording mode andcontrols the parameter selection circuit 35 to supply the compressionparameters for moving picture recording to the picture compressiondevice 25. The CPU 38 manages control to continue moving picturerecording as long as the moving picture recording button 36 remains inthe pressed-down state.

If the recording button for still picture 37 is pressed own, the CPU 38judges the recording mode to be the still picture recording mode andcauses the compression parameters for still picture to be supplied viaparameter selection circuit 35 to the picture compression device 25. TheCPU 38 terminates the still picture recording mode at a time point aone-frame still picture has been recorded as from the time point ofdetection of pressing down of the still picture recording button 37. Thearrangement may be made so that, as long as the still picture recordingbutton 35 is pressed down, still picture recording will be continuedwith a number of frames per unit time equal to that for moving picturerecording or with a number of frames per unit time smaller than that formoving picture recording.

If the still picture recording button 37 is pressed own in the state inwhich the moving picture recording button 36 is pressed down and therecording is going on with the moving picture recording mode, the CPU 38switches the compression parameters for one frame from those for movingpictures to those for still pictures. Meanwhile, the CPU 38 may causethe still picture recording mode to be continued as long as the stillpicture recording button 37 is pressed down.

Based on the picture compression parameters supplied from the picturecompression system switching device 30, the picture compression device25 compresses the input picture signals for conversion to picture data.When generating the picture compression data for still picture based onthe compression parameters supplied from the picture compression systemswitching device 30, the picture compression device 25 sets thequantization coefficient of the first macro-block to ‘1’. Whengenerating the picture compression data for moving picture based on thecompression parameters for moving picture recording, the picturecompression device 25 sets the quantization coefficient of the firstmacro-block to other than ‘1’.

By recording on the recording medium whether or not recording has beenmade with the still picture recording mode or with the moving picturerecording mode depending on whether the quantization coefficient of thefirst macro-block has been set to ‘1’, it becomes possible toautomatically select and reproduce only the still picture data duringreproduction.

The operation of the still/moving picture recording device 21 accordingto the present invention will be explained. If the moving picturerecording button 36 is pressed down, the CPU 38 in the picturecompression system switching device 30 judges the recording mode to bethe moving picture recording mode to send the compression parameters formoving picture recording to the picture compression device 25. Thepicture compression device 25 compresses the input picture based on thecompression parameters for moving picture recording and outputs thecompressed picture data. The recording data generating device 26 packetsthe speech data outputted by the speech compression device 23 and thepicture data outputted by the picture compression device 25 to supplythe resulting packet data to the recording device 27. The recordingdevice 27 records the packet data on an exchangeable recording medium28, such as a tape, disc or a memory card. This effects recording ofmoving pictures.

If the still picture recording button 15 is pressed, the CPU 38 in thepicture compression system switching device 30 judges the mode to be astill picture recording mode, and furnishes the compression parametersfor recording still pictures to the picture compression device 25. Basedon the compression parameters for recording still pictures, the picturecompression device 25 compresses the input picture for one frame tooutput the compressed picture data. The compressed one-frame picturedata is packeted by the recording data generating device 26 andfurnished to the recording device 7 for recording on the exchangeablerecording medium 28.

If the still picture recording button 37 is pressed down during therecording of moving pictures, the CPU 38 in the picture compressionsystem switching device 30 switches the picture compression parameterssupplied to the picture compression device 25 from those for movingpicture to those for still pictures only during one-frame period. Thus,the picture compression device 25 reverts to the state of compressingthe moving pictures after compressing the input picture based on thestill picture recording compression parameters for one frame as from thecompressed state for moving pictures. The picture data, sequentiallyoutputted by the picture compression device, is packeted by therecording data generating device 26 and thence supplied to the recordingdevice 27 for recording on the exchangeable recording medium 28.

Since only the compression parameters are modified for one frame periodof recording still picture, even if still picture is recorded duringrecording the moving pictures, but the series of moving picturerecording operations are not discontinued, so that still picture can berecorded without interrupting the recording of moving pictures.Consequently, the speech recording is not interrupted during recordingof the moving pictures. Moreover, if the moving and still pictures arerecorded simultaneously, the moving and still pictures are not recordedin separate areas, but simply the compression system for one-framepicture is modified for recording the one-frame still picture, so thatthe recording capacity of the recording medium can be exploitedeffectively without wastage. Also, since the one-frame input picture isrecorded in the still picture recording mode with low picturecompression ratio as an encoded frame reproducible within the frameitself, such as the intra-frame coed frame (I-picture), a still picturecan be recorded to a high picture quality.

In addition, the present still/moving picture recording device 1 recordson the recording medium data specifying whether the recording is by thestill picture recording mode or by the moving picture recording mode,depending on whether or not the quantization coefficient of the initialmacro-block of picture data is fixed at 1, so that it becomes possibleto select and reproduce only the still picture data automatically.

In the configuration of FIG. 2, the picture compression system switchingdevice 30 has the compression parameters for recording moving picturesand those for recording a still picture and the compression parametersconforming to the current recording mode are supplied from the picturecompression system switching device 30 to the picture compression device25. However, an arrangement may also be made so that compressionparameters for recording moving pictures and those for recording stillpictures are provided on the side of the picture compression device 25and so that a recording mode command indicating whether the recordingmode is that for the moving pictures or that for the still picture issupplied from the picture compression system switching device 30 to thepicture compression device 25 which then switches the picturecompression system depending on the supplied recording mode command.

An illustrative example of the still/moving picturerecording/reproducing device according to the present invention will beexplained by referring to FIG. 3.

A still/moving picture recording/reproducing device 100, shown in FIG.3, has the function of recording/reproducing speech and picture signals,and includes a speech input/output unit 111 for inputting/outputting thespeech signal, a speech compression/expansion processor 112 connected tothe speech input/output unit 111, a picture input/output unit 113 forinputting/outputting picture signals, a picture compression/expansionprocessor 114 connected to the picture input/output unit 113, a buffermemory unit 115 connected to the speech compression/expansion processor112 and to the picture compression/expansion processor 114, arecording/reproducing unit 116 connected to the buffer memory unit 115and a controller 117 for controlling the above components.

The speech input/output unit 111 includes an input amplifier circuit foramplifying the speech signal collected by a microphone not shown, to apre-set level and an output amplifier for circuit for amplifying theoutput speech signal to a pre-set level.

The speech compression/expansion processor 112 has its operating modeswitched by the controller 117 so that it operates during the recordingmode for digitizing the input speech signal and subsequentlyhigh-efficiency encodes the digitized data, by way of data compression,while operating during the playback mode for expanding the compressedspeech data for subsequently converting the compressed speech signalsinto analog signals. The speech compression/expansion processor 112includes an AD/DA converter circuit 121, an encoding/decoding circuit122 for compression/expansion and an interfacing circuit 123. The speechcompression/expansion processor 112 has its operating mode switched bythe controller 117 between an input mode and an output mode so that thecompression mode and the expansion mode will be set during the inputmode and during the output mode, respectively.

As the high-efficiency encoding compression system in the speechcompression/expansion processor 112, two systems, namely the sub-bandcoding exploiting the psychoacoustic characteristics of the humanauditory system (auditory masking effect and minimum audibilitycharacteristics) or adaptive transform acoustic coding (ATRAC), areused.

In the speech compression/expansion processor 112, the AD/DA convertercircuit 121 digitizes analog speech signals entered thereto via thespeech input/output unit 111 during the compression mode to transmit thedigital speech signals to the encoding/decoding circuit 122 forcompression/expansion. Also, the AD/DA converter circuit 121 convertsthe digital speech signals supplied during the expansion mode from theencoding/decoding circuit 122 for compression/expansion into analogsignals to output analog speech signals via the speech input/output unit111. During the compression mode, the encoding/decoding circuit 122 forcompression/expansion encodes the digital speech signals suppliedthereto from the speech input/output unit 111 via AD/DA convertercircuit 121 in accordance with the ATRAC2 system by way of datacompression for routing the compressed speech data via interfacingcircuit 123 to the buffer memory unit 115. Moreover, during theexpansion mode, the encoding/decoding circuit 122 forcompression/expansion decodes the compressed speech data suppliedthereto via interfacing circuit 123 as an opposite operation to encodingfor supplying digital speech signals to the AD/DA converter circuit 121.

The picture input/output unit 113 includes an imaging unit 124, animaging signal processor 125 and a picture signal output processor 126and has its operating mode switched by the controller 117 between theinput mode and the output mode.

The imaging unit 124 in the picture input/output unit 113 includes animaging lens 127 on which falls an imaging light beam, a CCD imagesensor 128 for imaging an object image via imaging lens 127, an analogsignal processing circuit 129 for taking out imaging signals from theCCD image sensor 128 for amplifying the imaging signal thus taken out toa pre-set level, and a timing generator 130 for supplying clock signalsto the analog signal processing circuit 129. The CCD image sensor 128 isa two-dimensional color image sensor made up of, for example, 768horizontal pixels by 494 vertical pixels, and outputs imaging signalscolor-coded by a color coding filter of the prime colors (R, G and B) orcomplementary colors (Ye, Cy and Mg). The analog signal processingcircuit 129 takes out from the CCD image sensor 128 the imaging signalsfreed of the reset noise by correlated double sampling and amplifies theimaging signals to a pre-set level by AGC to transmit the amplifiedimaging signal to the imaging signal processor 125.

Meanwhile, the timing generator 130 of the imaging unit 124 generatesvarious clocks required for driving the CCD image sensor 128, forcorrelative double sampling in the analog signal processing circuit 129and for driving the imaging signal processor 125 as later explained,using the original oscillation of 14.318 MHZ (4 fsc).

The imaging signal processor 125 in the picture input/output unit 113includes an A/D converter circuit 131 supplied with imaging signals fromthe imager 124, a digital signal processor 132 supplied with the digitalimaging signals from the A/D converter 131, a delay circuit 133connected to the digital signal processor 132 and a rate convertercircuit 134.

The A/D converter circuit 131 digitizes the imaging signals from theimaging unit 124 and routes the resulting imaging signals to the digitalsignal processor 132. The digital signal processor 132 decodes thedigital imaging signals supplied from the imager 124 via A/D converter131 in association with the color coding by the color coding filter ofthe CCD image sensor 128, using a delay circuit 133, for regeneratingthe luminance signal Y and the chroma signal Cr/Cb pursuant to the NTSCsystem. The rate convertor circuit 134 executes rate conversion ofchanging over the sampling frequency of the luminance signal Y and thechroma signal Cr/Cb board generated by the digital signal processor 132from 14.318 MHZ to 13.5 MHZ for generating the luminance signal Y andthe chroma signal Cr/Cb pursuant to CCIR60l.

In the picture input/output unit 113, the imaging unit 124 and theimaging signal processor 125 operate during the input mode. The imagingsignal processor 125 generates, from the imaging signals generated bythe imaging unit 124, the digital picture signals Y/Cr/Cb pursuant tothe CCIR601, and outputs the signal Y/Cr/Cb to the picture signal outputprocessor 126 and to the picture compressing/expansion processor 114.

The picture signal output processor 126 of the picture input/output unit113 includes a mixer circuit 136, fed with the digital picture signalsY/Cr/Cb generated by the imaging signal processor 125, pursuant toCCIR601, digital picture signals Y/Cr/Cb generated by the picturecompression/expansion processor 114 as later explained, pursuant toCCIR601, and a tube surface display signal generated by a tube surfacedisplay signal generating circuit 135. The picture signal outputprocessor 126 also includes a palette RAM 137 connected to the tubesurface display signal generating circuit 135, an NTSC encoding circuit138 connected to the mixer circuit 136 and a D/A converter circuit 139connected to the NTSC encoding circuit 138.

The mixer circuit 136 of the picture input/output unit 113 is used forsuperimposing a tube surface display signal generated by the tubesurface display signal generating circuit 135 on the digital picturesignals Y/Cr/Cb, pursuant to CCIR601, generated by the picture signalprocessor 125 or the picture compression/expansion processor 114. TheNTSC encoding circuit 138 encodes the digital picture signals Y/Cr/Cbpursuant to CCIR601 supplied by the picture signal processor 125 or thepicture compression/expansion processor 114 via mixer circuit 136 todigital picture signals pursuant to NTSC to transmit the resultingdigital picture signals to the D/A converter circuit 139. The D/Aconverter circuit 139 converts the digital picture signals supplied fromthe NTSC encoding circuit 138 into analog picture signals which areoutputted to for example a monitor device, not shown.

The picture compression/expansion processor 114 has its operating modechanged over by the controller 117 so that it operates as a datacompression device of high-efficiency encoding or compression for therecording mode, by way of data compression, while operating as a dataexpansion device of expanding the compressed picture data during theplayback mode. The picture compression/expansion processor 114 is madeup of a motion detection circuit 141 and an encoder/decoder circuit 142for compression/expansion and has its operating mode changed over by thecontroller 117 to an input mode or to an output mode or vice versa suchthat the compression mode and the expansion mode are set for the inputmode and for the output mode, respectively.

As the high-efficiency encoding compression system in the picturecompression/expansion processor 114, the MPEG (Moving Picture ExpertsGroup) 2 system exploiting correlation of picture signals is used. Withthe MPEG2 system, the inter-frame difference of picture signals is takenfor lowering redundancy along the time axis and subsequently theorthogonal transform technique such as discrete cosine transform is usedfor lowering redundancy along the spatial axis for high-efficiencyencoding the video signals. With the MPEG system, a group consisting ofa number of moving pictures is termed a group-of-pictures (GOP) andpicture reproduction is carried out on the GOP basis. The pictures in aGOP are roughly classified into an I-picture, a P-picture and aB-picture, with the picture signals of each frame being encoded as onesuch picture type.

In the picture compression/expansion processor 114, the encoder/decodercircuit 142 for compression/expansion encodes the digital picturesignals Y/Cr/Cb pursuant to CCIR601, supplied from the pictureinput/output unit 113 via motion detection circuit 141 for thecompression mode, in accordance with the MPEG2 system, by way of datacompression, for generating compressed picture data, which is thensupplied to the buffer memory unit 115. The amount of generated bits isfed back from the encoder/decoder circuit 142 to the motion detectioncircuit 141 for effecting rate control. Picture data is compressed underthe picture compression conditions designated by the compressionparameters supplied from the controller 117. The encoder/decoder circuit142 for compression/expansion decodes the compressed picture data fromthe buffer memory unit 115 as a counterpart operation to encoding forgenerating digital picture signals Y/Cr/Cb pursuant to CCIR601 forsupplying the generated picture signals to the mixer circuit 136 of thepicture input/output unit 113. The amount of generated bits is fed backfrom the encoder/decoder circuit 142 to the motion detection circuit 141for effecting rate control.

The buffer memory unit 115, used for transiently storing compressedspeech data and compressed picture data recorded/reproduced by therecording/reproducing unit 116, is made up of a buffer controller 151and a cache memory 152 and is switched between the input and outputmodes by the controller 117.

If the input mode is set by the controller 117, the buffer controller151 of the buffer memory unit 115 transiently stores compressed speechdata supplied from the speech compression/expansion processor 112 andcompressed picture data supplied from the picture compression/expansionprocessing unit 114 in the cache memory 152 and packets the compressedspeech data and the compressed picture data to form packet data which issupplied to the recording/reproducing unit 116. If the output mode isset by the controller 117, the buffer controller 151 transiently storesthe packet data from the recording/reproducing unit 116 in the cachememory 152 for separately supplying the compressed speech data and thecompressed picture data to the speech compression/expansion processor112 and to the picture compression/expansion processor 114,respectively.

The recording/reproducing unit 116 records/reproduces picture and speechdata, using a magneto-optical disc 160, having a double spiral track asproposed in our co-pending Japanese Patent Applications Nos. 8-67880 or9-142664, as a recording medium. The recording/reproducing unit 116includes a recording unit 162 and a reproducing unit 163, connected viaan interfacing circuit 161 to the buffer memory unit 115, and has itsoperating mode changed over by the controller 117.

In the recording/reproducing unit 116, the recording unit 162 includes arecording encoder 164, fed with the packet data from the buffer memoryunit 115 via interfacing circuit 161, a recording driver 165 driven byan output of the recording encoder 164 and a magnetic head 166 excitedby the recording driver 165. The reproducing unit 163 is made up of anoptical head 167 arranged facing the magnetic head 166 with themagneto-optical disc 160 inbetween, a playback amplifier 168 connectedto the optical head 167, an A/D converter 170 and an ADIP decoder 169,fed with playback signals by the optical head 167 via playback amplifier168, a viterbi decoding circuit 171 fed with an output of the A/Dconverter circuit 170, and a playback decoder 172 fed with outputs ofthe address in pre-groove decoder (ADIP decoder) 169 and the viterbidecoding circuit 171.

By the recording mode being set by the controller 117 for the input modein the recorder 162 in the recording/reproducing unit 116, the packetdata from the buffer memory unit 115 is fed to the recording encoder 164via interfacing circuit 161. By the packet data being modulated and bythe resulting modulated output driving the recording driver 165, therecording encoder 164 energizes the magnetic head 166 in keeping withpacket data. In the recording/reproducing unit 116, the laser lightilluminated on the magneto-optical disc 160 from the optical head 167 ofthe reproducing unit 163 arranged facing the magnetic head 166 with themagneto-optical disc 160 in-between is switched for the recording modeto the recording light volume for raising the temperature of themagneto-optical recording layer of the magneto-optical disc 160 to theCurie temperature by laser light illumination. Under this condition, themagnetic head 166 is energized for magnetic field modulation recordingthe packet data on the magneto-optical recording layer of themagneto-optical disc 160.

By the playback mode being set for the output mode in the playback unit163 in the recording/reproducing unit 116 by the controller 117, thelaser light illuminated from the optical head 167 to the magneto-opticaldisc 160 is switched to the playback light volume. The optical head 167radiates the laser light of the playback light volume to themagneto-optical recording layer of the magneto-optical disc 160 anddetects the reflected light for reproducing the playback signal. Theplayback signals generated by the optical head 167 are supplied viaplayback amplifier 168 to the A/D converter circuit 170 and to the ADIPdecoder 169. The playback signals supplied to the A/D converter circuit170 are digitized and viterbi-decoded by the viterbi decoding circuit171 to give playback data. The viterbi decoding circuit 171 furnishesthe viterbi-decoded playback data to the reproducing decoder 172. TheADIP decoder 169 decodes the address information recorded as ADIP signalby for example bi-phase modulating the wobbling of the groove of themagneto-optical disc 160 from the playback signals and furnishes thedecoded address information to the reproducing decoder 172. The playbackdecoder 172 demodulates the playback data in association with theencoding performed by the recording encoder 164 of therecording/reproducing unit 116 for reproducing the packet data which issupplied via interfacing circuit 161 to the buffer memory unit 115.

The controller 117 is comprised of a micro-processor 180 and operates asa system controller for switching the operation of the speechcompression/expansion processor 112, picture input/output unit 113,picture compression/expansion processing unit 114, buffer memory unit115 and the recording/reproducing unit 116.

The micro-processor 180 in the controller 117 accepts an operating inputof a still picture recording button 181 or a moving picture recordingbutton 182 to switch between the still picture mode and the movingpicture mode and determines the picture compression parameters, that isquantization parameters, supplied to the picture compression/expansionprocessor 114, in accordance with the flowchart shown in FIG. 4.

That is, the micro-processor 180 of the controller 117 determines thedata volume allocated to a frame at step S1 as follows: That is, if ratecontrol is executed on the GOP basis, the total number of GOP-based datais found from the bit rate and the data volume so far used is subtractedfrom the total number of data to find the residual data volume. Thenumbers of the residual I-, P- and B-pictures are then found for settingdata allocation. Finally, the data volume is determined in accordancewith the frame compression method (I, P and B).

At the next step S2, it is judged whether the operating mode is thestill picture mode or the moving picture mode. If the mode is the stillpicture mode, the data volume is increased in an amount designated atstep S3. Then, processing transfers to step S4. If the mode is themoving picture mode, processing transfers directly to step S4.

At step S4, the initial value of the quantization coefficient is set asfollows: That is, the data volume as found is divided by the totalnumber of macro-blocks to set the data rate as an initial value of thequantization coefficient.

At the next step S5, it is judged whether or not the current value ofthe generated data volume is smaller than a target value. If the currentdata rate is smaller than the target value, processing transfers to stepS6 to lessen the quantization coefficient. If the current data rate islarger than the target value, processing transfers to step S7 to enlargethe quantization coefficient.

At the next step S8, it is judged whether the operating mode is thestill picture mode or the moving picture mode. If the mode is the movingpicture mode, processing reverts to step S5 to judge again whether ornot the current value of the generated data volume is smaller than thetarget value.

At the next step S9, it is judged whether or not the motion vector islarger than a threshold value. If the motion vector is smaller than thethreshold value, processing transfers to step S10 to lessen thequantization coefficient. If the motion vector is larger than thethreshold value, processing transfers to step S11 to enlarge thequantization coefficient.

At the next step S12, it is judged whether a block in subject is in apre-set mid portion on the screen or in any other peripheral portion. Ifthe block is in the mid portion of the screen, processing transfers tostep S13 to lessen the quantization coefficient. If the block is in theperipheral portion of the screen, processing transfers to step S14 toenlarge the quantization coefficient. Then, processing reverts to StepS5 or judge again whether or not the current value of the generated datavolume is smaller than the target value.

With the present still/moving picture recording/reproducing device 100,in which the compression parameters for recording moving and stillpictures are adaptively determined and the compression parametersconforming to the recording mode are supplied from the controller 117 tothe picture compression/expansion processor 114 for preferentiallyallocating the information volume to a target desired to be imaged forthereby improving the picture quality of the still picture.

What is claimed is:
 1. A still/moving picture recording apparatuscomprising: picture compression means for generating, for a movingpicture recording mode, picture data compressed based on compressionparameters for moving picture recording, and for generating, for a stillpicture recording mode, compressed picture data compressed based oncompression parameters for still picture recording; and recording meansfor recording picture data generated by said picture compression meanson an exchangeable recording medium, wherein picture data inclusive ofthe still picture recording mode information specifying that the pictureis a still picture is recorded on said recording medium for the stillpicture recording mode, and wherein said compression parameters for thestill picture provide that, in compression encoding the compressionparameters for still picture in accordance with MPEG as the standard forencoding, the quantization coefficient of the first macro-block of thepicture data be fixed at a pre-set specified value, and wherein theinformation in which the quantization coefficient of the firstmacroblock of the picture data is fixed at the pre-set specified valueis utilized as the still picture recording mode information.
 2. A stillpicture recording method: wherein, for a moving picture recording mode,picture data compressed based on compression parameters for movingpicture recording is generated for recording on a recording medium,wherein, for a still picture recording mode, picture data compressedbased on compression parameters for still picture recording is generatedbased for recording on the recording medium along with the still picturerecording mode information specifying that the picture recorded in astill picture, and wherein the compression parameters for still pictureprovide that, in compression encoding by MPEG as a standard forencoding, the quantization coefficient of the initial macro-block ofpicture data be fixed at a pre-set specified value, and wherein theinformation in which the quantization coefficient of the initialmacro-block of picture data is fixed at the pre-set specified value isused as the still picture recording mode information.